Scientists unlock new way to control molecules with light, sidestepping old tradeoffs
Researchers have demonstrated five techniques for triggering molecular switches using indirect light pathways, avoiding the stability problems that plague conventional photoswitches. The advances could accelerate development of light-activated drugs, smart materials, and diagnostic tools that respond to safer wavelengths of light.
Originaltitel: Detour to success: photoswitching <em>via</em> indirect excitation
<p>Photoswitchable molecules that undergo nanoscopic changes upon photoisomerisation can be harnessed to control macroscopic properties such as colour, solubility, shape, and motion of the systems they are incorporated into. These molecules find applications in various fields of chemistry, physics, biology, and materials science. Until recently, research efforts have focused on the design of efficient photoswitches responsive to low-energy (red or near-infrared) irradiation, which however may compromise other molecular properties such as thermal stability and robustness. Indirect isomerisation methods enable photoisomerisation with low-energy photons without altering the photoswitch core, and also open up new avenues in controlling the thermal switching mechanism. In this perspective, we present the state of the art of five indirect excitation methods: two-photon excitation, triplet sensitisation, photon upconversion, photoinduced electron transfer, and indirect thermal methods. Each impacts our understanding of the fundamental physicochemical properties of photochemical switches, and offers unique application prospects in biomedical technologies and beyond.</p>